A New Methodology for the Structural Analysis of 3D Digitized Cultural Heritage through FEA

Abstract

Abstract. Finite Elements Analysis (FEA) is widely used for modelling stress behaviour in any mechanical system. The processing workflow starts from CAD 3D models representing the ideal shape of the object to be simulated. Such models are typically made of mathematical elements defining its geometrical components. Those are pre-processed before the simulation for creating a volumetric mesh out of the CAD model. Recently the use of FEA has also been extended to the simulation of ancient structures and artefacts, revealing significant potentialities for the conservation of Cultural Heritage. Unlike modern mechanical systems, heritage objects are usually altered by the time passed since their original creation, and the representation with a schematic CAD model may introduce an excessive level of approximation leading to wrong simulation results. In the last two decades, 3D documentation of CH has been developed through reality-based approaches. However, the related mesh models of the exterior surfaces are not proper for direct use in FEA. Such high-resolution surface meshes has to be converted to volumetric meshes made of tetrahedral or hexahedral elementary volumes and a limited number of external and internal nodes. The focus of this paper is on a new method aiming at generating the best possible 3D solid representation of a real artefact from its accurate reality-based surface model by reducing its number of nodes of several orders of magnitude while maintaining a geometrical coherence in the order of the measurement uncertainty of the 3D capturing technique used. The approach proposed is based on wise use of retopology procedures and a transformation of this retopologized model to a mathematical one made by NURBS surfaces, suitable for being processed by a volumetric mesh generator typically embedded in any standard FEM package. The resulting volumetric mesh allows obtaining FEA of ancient structures, providing a far better accurate simulation than those attainable by a rough CAD redrawing of the heritage asset of interest.

Point Cloud Exploitation for Structural Modeling and Analysis: A Reliable Workflow

“…As mentioned above, the construction of nurbs curves that generate a nurbs surface is unsuitable for the complexity of the geometry of an historical architecture. There is, however, an convincing approach (Barsanti and Guidi, 2018), based on quadrangular meshes instead of triangular ones. It mainly consists in rearranging the initial topology of the mesh, thus it is called Retopology.…”

Solid Model Generation for Digitized Organic Bodies via T-Splines

“…Examples of reverse engineering projects in the case of heritage objects are illustrated in References [32][33][34][35][36][37][38][39]. Digitization was carried out with different techniques for different purposes, such as finite element analysis, virtual museums, better understanding of museum collections, risk evaluation, deformation analysis and monitoring, among others.…”

Synergy of LIDAR and hyperspectral remote sensing: health status assessment of architectural heritage based on normal cloud theory and variable weight theory

“…However, this cannot determine the force condition of the structure under external forces, which means that the spatial data model alone is insufficient to support the structural analysis of architectural heritage. The literature [9][10][11][12] used the finite element method to perform structural force analysis by approximating the solid structure with discrete grid cells. However, since the network models used are usually created in CAD software, they cannot be strictly considered "reality-based" 3D models and are not entirely consistent with natural objects, resulting in distorted results of FEM structural analysis.…”